Linde North America has begun the process for a major overhaul of two of its air separation units (ASUs) after renewing long-term contracts with two of its major tonnage customers.

The overhauls will assure continuity of supply throughout the length of the new supply agreements with a metallurgical operation in Trail, BC, Canada, and with a major steel manufacturer in Braddock, Pennsylvania.

Linde has been supplying oxygen and nitrogen to Teck Metals Trail Operations for its zinc and lead smelting and refinery complex since 1989. “With the new supply agreement that will run until 2036, Linde has completed a ‘relife’ of the ASU, an extensive upgrade that increases the efficiency and capacity of the plant, and extends its operating life,” said Ray Carr, vice president, Tonnage Business, Americas, for Linde.

The plant overhaul included a cooling water project to create a more efficient system that will use considerably less water in the cooling process. It also included refurbishment or upgrading several compressors, an upgrade to the control system and installation of new instruments and analysers, as well as other process equipment. “This plant upgrade will assure product to Teck for the life of the contract and beyond. It will also allow the plant to produce additional liquid argon which we’ll deliver by truck to semiconductor customers in northwestern US,” Carr said.

Linde built a large ASU in Braddock, Pennsylvania, in 1997 to supply steel-making facilities for a major steel company. The plant will undergo its first complete overhaul to satisfy the contract that has been renewed for an additional 15 years.

Carr said, “The overhaul of the plant will not only increase its efficiency and reliability to supply oxygen and nitrogen gas via pipeline to the steel plant; it will also increase our capacity to produce liquid oxygen, nitrogen and argon for the merchant markets in the northeast.”

The facility will shut down in the spring of 2015 for 45 days to complete an extensive scope of work. The overhaul will refurbish or upgrade every system of the Braddock ASU, including compressors, heat exchangers, and distillation equipment. Linde will also modernise the entire control system.